Sure, there are plenty of researchers working on fanciful daydreams. They pursue those goals at behest of their employer. You attempted to make a distinction between the employer and the employee's goals, as though a Distinguished Engineer at Microsoft was just playing around on a whim doing hobby projects for fun. If Microsoft is paying him $1m annually to work on this, plus giving him a team to pursue the goal of rewriting Windows, it is not inaccurate to state that Microsoft's goal is to completely rewrite Windows with LLMs, and they will earn negative publicity for making that fact public. The project will likely fail given how ridiculous it is, but it is still a goal they are funding.
Microsoft funded Simon Peyton-Jones (Haskell) and Don Syme (F#) and SP-J worked on Excel, but it would be inaccurate to say that their goal was to rewrite Excel, Windows, C#, .NET into functional programming. Yes, to an extent researchers "play around on a whim doing hobby projects for fun", or more formally as SP-J said in an interview "the mission statement that Microsoft Research had at that time which was to push forward the boundaries of knowledge; put Microsoft in a position to be agile when new stuff heaves over the horizon; provide a reservoir of expertise for the rest of the company to draw on".
- https://archivesit.org.uk/interviews/simon-peyton-jones/
Otherwise your position is that "blue-sky research" doesn't exist (it does) or that big companies don't fund it (they do). In particular, the LinkedIn in question said nothing about "Windows", that is something internet has hallucinated to maximise ragebait.